New 4th Domain of Life discovered?

The 5 kingdoms of life (plants, animals, fungi, Protista, bacteria) was replaced by the 3 Domains of life (eukarya = plants, animals, fungi and Protista; bacteria; and archea = extremophiles).

Now biologists have discovered 2 new species of giant viruses (that are bigger than some bacteria and can be seen using light microscopes) that have huge genomes (over 1000 genes, most viruses have less than 10 genes) and most of their genes a completely new to science (meaning they are evolutionarily not related to any other known life form)

Yeah, though the bit about the virusinside the amoeba that lived in a contact lense that woman put into her eye everyday is chilling.
One reason not to use permanent lenses an sterilising them every day.

I can't help but wonder if--back when the earth was hotter--we had smokers near river deltas.

Vortex-stirring of organics might be a good way to spin up life. Biology only takes you so far back--and chemistry only so far forward.

This is why folks don't understand evolution. It wasn't just a warm pond where something just happened. We have had impacts, smokers, huge tides stirring things up--it is all very active. The ponds are just shelters where life can catch its breath for a moment and flourish.

...and most of their genes a completely new to science (meaning they are evolutionarily not related to any other known life form)

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Would this then be evidence of abiogenesis occurring more than once, or do you mean something else?

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It could be - there is still so much we don't know. I think it's unlikely that life only started once and that everything evolved from that first single cell (seems to Adam and Eve to me). I'm sure life occurred several times, some lineages died out, some combined (like ancient archea and bacteria fusing to become eukaryotes, or modern bacteria swapping plasmids). What ever the truth is, it's probably way more complicated than we think (and ultimately unknowable, it will just be hypotheses and conjecture)

I read a hypothesis that these megaviruses might have once been proper cells, which might explain their large genomes (this doesn't feel right to me as it doesn't explain where their protein coat came from)

...and most of their genes a completely new to science (meaning they are evolutionarily not related to any other known life form)

Click to expand...

Would this then be evidence of abiogenesis occurring more than once, or do you mean something else?

Click to expand...

It could be - there is still so much we don't know.

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It would be interesting to see what they get from sequencing the genome of these new things.

I think it's unlikely that life only started once and that everything evolved from that first single cell (seems to Adam and Eve to me). I'm sure life occurred several times, some lineages died out, some combined (like ancient archea and bacteria fusing to become eukaryotes, or modern bacteria swapping plasmids).

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If that's the case, we should see that the genetic code of the organelles is significantly different to the code of the nucleus. My understanding is that this isn't the case.

What ever the truth is, it's probably way more complicated than we think (and ultimately unknowable, it will just be hypotheses and conjecture)

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True, it will turn out to be quite complicated, I think, but I think we'll be able to figure out enough to get a very good idea of what actually happened.

Would this then be evidence of abiogenesis occurring more than once, or do you mean something else?

Click to expand...

It could be - there is still so much we don't know.

Click to expand...

It would be interesting to see what they get from sequencing the genome of these new things.

I think it's unlikely that life only started once and that everything evolved from that first single cell (seems to Adam and Eve to me). I'm sure life occurred several times, some lineages died out, some combined (like ancient archea and bacteria fusing to become eukaryotes, or modern bacteria swapping plasmids).

Click to expand...

If that's the case, we should see that the genetic code of the organelles is significantly different to the code of the nucleus. My understanding is that this isn't the case.

Click to expand...

To the best of my knowledge mitochondrial and chloroplast DNA is bacterial in origin and nuclear DNA is Archean in origin. I can't remember if I read that in an article or saw it in a doco so I can't verify that claim

It would be interesting to see what they get from sequencing the genome of these new things.

I think it's unlikely that life only started once and that everything evolved from that first single cell (seems to Adam and Eve to me). I'm sure life occurred several times, some lineages died out, some combined (like ancient archea and bacteria fusing to become eukaryotes, or modern bacteria swapping plasmids).

Click to expand...

If that's the case, we should see that the genetic code of the organelles is significantly different to the code of the nucleus. My understanding is that this isn't the case.

Click to expand...

To the best of my knowledge mitochondrial and chloroplast DNA is bacterial in origin and nuclear DNA is Archean in origin. I can't remember if I read that in an article or saw it in a doco so I can't verify that claim

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Yes, but the bacteria and the archea both came from a common ancestor. They aren't the results of two completely independent rises of life.

^I think it's highly unlikely it came from Mars, or even a completely separate biogenesis. That's because, as a virus that uses the cellular machinery of another cell, it of necessity must use the same genetic code, nucleic acids, and amino acids as other forms of life. A completely separate biogenesis event, whether on this planet, or another, would almost certainly use a different genetic code and likely a different set of amino acids and nucleic acids.

If there's anything to the idea of panspermia, then there would have been only one biogenesis event in the galaxy. That idea goes the opposite direction of arguing for a separate biogenesis for these viruses.